a,Với đk đề cho ta có biểu thức tương đương :
\(\dfrac{\sqrt{x}+1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}+\dfrac{\sqrt{x}-1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}+\dfrac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\)
=\(\dfrac{\sqrt{x}+1+\sqrt{x}-1+x-1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}\)=\(\dfrac{x+2\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)